LTE handles lot of data, packet switched traffic data.
Throughput in LTE is shared in both time and frequency.
The throughput in LTE is very high compared to other 3GPP and legacy networks, it can provide high data throughput in both downlink as well as uplink with the help of new multiplexing techniques such as OFDMA and SCFDMA implemented in LTE, these are the modified versions of the Frequency Division i.e., FDMA previously used in GSM.
The high data throughput is also dedicated to other techniques used such as advanced antenna techniques – MIMO and better modulation such as 16 QAM and 64 QAM made available in LTE.
The maximum throughput that can be achieved at cell level with using maximum QAM and MIMO is nearly 300 Mbps in the downlink and 75 Mbps in Uplink, provided the UE category is capable of this and also the MIMO is supported only in the Downlink so far.
With carrier aggregation being introduced through the LTE- Advanced even greater throughput can be experienced at cell level and even also at individual users quiet soon.
Entering into more practical situations of LTE where we are limited to use MIMO and QAM for QoS requirements and also other factors such as limited bandwidth available at one respective cell, the throughput will not be the same at every possible location in the cell radius, sometimes gradually reducing as we near the cell edge and other times occasionally drastically dropping causing dissatisfaction for the customers.
What could be the reason?
It is not very difficult to deduce that the gradual drop of throughput towards the cell edge is more because of poor quality and also lesser bandwidth available at cell edge when the bandwidth is being shared with neighbouring sectors to avoid ICI.
But, for more drastic degradation of throughput.
It is popular belief among RF Engineers that the SINR is the main reason for Throughput drop.
Whereas the actuality is that SINR is only representation of throughput at any cell, i.e., SINR is directly proportional to Throughput.
Whenever SINR is seen less range, the throughput will also be seen at its lower values and vice versa.
This all means that the cell requires troubleshooting of various kinds, such as RF tuning, RBS troubleshooting, Cell and Base station capacity, Call admission control, etc.